THE JUDGE glared disdainfully down from the bench at the man he was about to sentence.

"You should be thankful young man," he said, "thankful that someone had the foresight to hire Ken Mundy as your attorney."

The words were hardly comforting to Mundy because Judge Jacob S. Levin then sentenced his client, 16-year-old Terrence G. Johnson, to 25 years in jail - the maximum - for his role in killing two Prince George's County police officers last summer.

To Mundy the sentence was harsh and unexpected. The trial had been a victory. It had given him the opportunity again to show why he is considered one of Washington's top criminal lawyers and is widely admired and respected.

When Mundy agreed to take the case he appeared to have an impossible task. There was no disputing that Johnson, who had a juvenile record filled with assaults, had shot and killed officers. Albert M. Clagget IV and James Brain Swart in the Hyattsville police station in June 1978.

But Mundy took the case, knowing that the racial overtones - a black youth killing two white officers - and the defendant's age would make it a highly publicized one. And one he believed he could win.

"Before every case I write a little note to myself predicting the outcome," Mundy said. "I think of the eworst eventualities and what I will do to combat them. When I thought of this one, I didn't think they would convict on first degree murder."

Few people would have predicted the outcome: guilty only of manslaughter and illegal use of a hundgun for killing Clagget and not guilty by reason of insanity for killing Swart.

Another notch in Ken Mundy's belt. But it is by winning difficult cases that he has built his reputation in 14 years in private practice.

Among his more notable courtroom victories are:

The Fishmarket murders. Mundy defended Melvin Downing, who was accused of chopping three men to death with a machete during a robbery. A fourth victim survived and identified Downing in court as one of three assailants. Downing was acquitted.

The William Wynn case. Wynn was charged with shooting and then cutting the throat of an elderly woman. The gun identified as the murder weapon was found in his chandlier. Witnesses saw Wynn leaving the building where the woman lived a short time before the body was found. Wynn was acquitted.

The Sterling Tucker case. Proving his versatility, Mundy defended the former city council president in his legal battle two years ago with the city's corporation council, John Risher, over Tucker's part-ime teaching for pay at Howard University. Tucker was cleared.

Mundy does not like to think he has gotten guilty men off in acquittals for men like Downing and Wynn. In fact, he admits that when he finds after a case is over that he has freed a guilty man, he broods about it.

"I like to think it doesn't happen often," he says. "And I try to think that I've saved more innocent men from being found guilty than the other way around."

Most of the time Mundy is pragmatic about his work - once a case is over he puts it behind him. But there are exceptions.

"Some cases are over and you forget them," he says. "Others, you lie awake in bed and think about over and over again. I've had a few where a guy has gotten off and then gone out and hurt someone badly. Those are very harrd to deal with. Those are the ones you lose sleep over."

All those who know Mundy and have watched him over the years agree on one thing: It is his power with words his almost unequalled ability as an orator which sets him apart from other lawyers.

That ability was on display during the Johnson trial, when, in the opinion of most observers, Mundy turned the case around with a spellbinding 95-minute closing argument.

Part of Mundy's success begins with his appearance. He looks like a person people trust. He is impeccable, his suits pressed and clean, his stylish goatee and mustache neatly trimmed and, for a touch of flair, he has a collection of berets, and is usually seen wearing one.

Even sitting in the recreation room of his spacious home in Kensington, dressed in blue jeans and a T-shirt, he looks neat. His narrow eyes widen as he listens and he laughts easily, often turning jokes on himself.

At 47, he is proud of his youthful appearance, and works at it. A former Golden Gloves boxer, he still has a set of weights in his basement and plays tennis and skis to keep in shape. He brightens when told he looks youthful.

"Yeah, I know," he says, running his hand over his head. "If I'd kept my hair, I'd look younger. Too bad."

Friends say that Ken Mundy is driven by a combination of natural competitiveness, pride and a feeling that a defense attorney takes on a heavy responsibility when he agrees to take a case.

"The Johnson trial was really traumatic for me," Mundy says. He is sitting in a comfortable chair overlooking his pool. "I remember during my closing argument I would occasionally look over towards Terry and I would think again and again, 'He's only 16 and he's depending on you.' It was a heavy burden."

But Mundy was not about to turn down the Johnson case. Even when the defense fund's money ran out and he was only paid $12,000 of his $20,000 fee, he remained with the case for a number of reasons, not the least of which was the publicity. "The publicity alone made up for not getting the full fee," he admits.

But there was more to it than publicity. Terrence Johnson, as with Melvin Downing or William Wynn, provided a chance to prove that he could do what other lawyers could not do and it was Mundy's chance to help a black in trouble.

"I remember several times during the trial sitting next to Terry I would find myself thinking this could be my son [his son, Kip, is 17] and that if he were ever in trouble this way or any way, I would hope that somebody would try to help him, no matter how wrong he might look on the face of things or how tough the situation was. As much as anything I wanted to help Terry simply because he needed help and I thought he was entitled to it."

Or, as one friend pointed out: "Ken isn't an egotist but he is aware of his talents. He knows he is sometimes capable of making juries see things other lawyers might not get through to them. I think he honestly believes that if he is defending someone that person has as good a chance of getting a fair shake or even a better chance because he's his lawyer."

Mundy does not argue with that analysis. "I'd like to think that my closing argument had something to do with the Johnson verdict," he said, "because if it did, that's a feather in my cap."

Ronald Kenneth Mundy grew up in Akron, Ohio, the son of a factory. He wasn't sure what he wanted to do with his life beyond one thing: "I didn't want to do something run-of-the-mill. I wanted to do something beyond the ordinary so that when I looked back on my life I could feel as if I made a mark somewhere, contributed something."

Mundy figured out quite early that school was important to a young black, because as he puts it, "the only way to get out of spending your life on a menial job was college. I know I had to go to college." He still feels that way today and did not hesitate to discipline his son when his school grades dropped recently.

After graduation from Kent State University he took a year off before finally deciding to study law. His wife Mignon, whom he married as a college sophomore, paid the bills at Case Western Reserve Law School.

"I really wasn't sure what I wanted to do," he said of his derision to go to law school. "I had taken part in debates as a kid and found that I was good at it, that I enjoyed public speaking. Law seemed as good as anything else and I knew it would give me a chance to speak in public if I turned out to be a trial lawyer."

He quickly decided that he had made the right choice, taking to his law books with the same enthusiasm that he had taken to his boxing gloves as a teen-ager.

After getting his degree Mundy became one of the first black attorneys hired by the federal regulatory agencies when he went to work for the Federal Communications Commission. He stayed there for seven years before setting up in private practice with a friend in 1965. A year later he moved into offices at 16th and K streets NW, one of the first black firms in Washington west of 14th Street. Today, he has an elegant suite of offices further uptown and picks and chooses his clients carefully.

His partner Joseph Gibson, who has worked with Mundy for 13 years and was his co-counsel during the Johnson trial, admits that even though he has seen the routine over and over again, "He still leaves spellbound once in a while.

"Ken will deal with each jury differently," Gibson continued. "An all black jury, he'll probably start preaching. An all white jury, he'll be very factual in most cases.

"But he always has that tremendous memory to fall back on in any case. He never rehearses or anything. We go over the facts and the law and then he comes up with the words. I just sit back and watch."

On judge who sat in one parts of the Johnson trial was more succinct: "Ken Mundy may not be the best lawyer who ever lived," he said, "but he may be one of the best orators."

Perhaps the important factor in Ken Mundy's success is his ability to remain pragmatic, no matter what the case, no matter who the client.

Prosecutor Arthur A. Marshall Jr. cried after the Johnson trial verdict was delivered. Mundy was not even in the courtroom. He had flown to West Virginia on another case as soon as closing arguments had ended.

"The one thing a lawyer cannot afford to do is become too emotionally involved in a case," Mundy said. "A little is good but too much is bad. I purposely tried not to become too close to Terry and his family during this case, although we are cloase now.

"I wanted to be in complete control, especially during the closing argument. I didn't want to say or do anything I would regret later on.I can walk away from this feeling I did the best I could."

Beyond that, even he can walk away from a case which divided a community along racial lines and caused the police to go on strike for a day to protest the verdict, having made some new friends.

"Ken Mundy is as good a defense attorney as I've ever faced and I've seen a lot of lawyers in 16 years," Marshall said. "What's more he's a nice guy. I like him.And if I like him, a jury's going to like him."

Others who have opposed him in court have the same analysis. "You'll never hear Ken Mundy criticize someone or complain. You'll never hear him put someone down or make excuses," said Marshall's assistant, Edmond B. O'Connell. "He'll come at you with all he's got but when it's over, it's over, you're friends again. He's got class, lots of class."

That class was evident the day of the Johnson sentencing. First Mundy listened as Marshall in his argument for the maximum sentence accused him of putting the police department on trial. Then he listened helplessly as the judge handled down the sentence.

Disappointed, Mundy went outside the courthouse and spent over an hour answering reporters' questions. Finally, the crowd broke up. As Mundy walked away, a reporter saw him heading toward the courthouse entrance and asked him why he was going back inside.

"Oh, I just want to go upstairs and thank Bud [Marshall] for all his courtesy during the trial and say goodbye to him," Mundy answered.

Mundy then headed back to Washington to his case load, one that is much heavier than a lawyer with a successful practice normally handles personally.

"Criminal law is still my first love," he said. "I do a lot of civil cases now but I love criminal cases. I enjoy being in the courtroom atmosphere of a trial where the stakes ae high, a lot of people are watching and the pressure is on.

"If I ever stop doing it, I'll be like a race horse put out to pasture."

Mundy has not intention of heading to pasture or anywhere else. A judgeship does not interest him. He just wants to continue being the good lawyer he know he is.

And he will continue to get big cases just as long as he can handle himself the way he did before the Johnson jury, turning the steamy Upper Marlboro courtroom into his stage.

Pacing up and down in front of the jury box, apparently claim except for tiny beads of sweat showing around his goatee and moustache, Mundy slowly took the jury through the nightmarish morning of June 26, 1978.

"Please listen carefully," he began softly, "because I will have only one chance to put before you the case of Terrence Johnson."

"Criminal cases are built on human tragedy," he said. "This case is triply so because three people and three families have been affected by it.

"But Terrence Johnson is not a cold-murderer as the state would have you believe," Mundy said, voice rising. "He is a child who was in a state of fear almost beyond our comprehension that morning."

Finally, voice almost a whisper, "this trial is a search for the truth. And after we are finished here, you will speak the final judgment." CAPTION: Picture 1, Lawyer R. Kenneth Mundy in his K Street office, above, top photo by Gerald Martineau - The Washington Post; Picture 2, and Terrence Johnson being led from the Upper Marlboro courthouse after he was found guilty of manslaughter, left. Left photo by Douglas Chevalier;